From 4909122fb8350e70c347f1201256908a92058044 Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Mon, 8 Jun 2009 00:20:01 -0700 Subject: [PATCH] tun: Optimise handling of bogus gso->hdr_len As all current versions of virtio_net generate a value for the header length that's too small, we should optimise this so that we don't copy it twice. This can be done by ensuring that it is at least as large as the place where we'll write the checksum. Signed-off-by: Herbert Xu Signed-off-by: David S. Miller --- drivers/net/tun.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/net/tun.c b/drivers/net/tun.c index 3f0cdc14be82..8d82511aa1bc 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -565,6 +565,10 @@ static __inline__ ssize_t tun_get_user(struct tun_struct *tun, if (memcpy_fromiovecend((void *)&gso, iv, offset, sizeof(gso))) return -EFAULT; + if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) && + gso.csum_start + gso.csum_offset + 2 > gso.hdr_len) + gso.hdr_len = gso.csum_start + gso.csum_offset + 2; + if (gso.hdr_len > len) return -EINVAL; offset += sizeof(pi); -- 2.20.1